Well, here's the the tank I did:
I hacked it back aggressively 4x a month, about 50% each time.
So it had a doubling of bass every 2 weeks.
Just flourite, rock hard water, CO2, normal EI dosing, no GH obviously, TMG etc.
I can get the plant to turn green or redder with NO3.
I have several 35mm slide pics that are real nice, but have not been able to scan them well.
Maybe it is lighting..........
Regards,
Tom Barr